Socket and snap-in contact for printed circuits



Nov. 18, 1958 B. J. JOHANSON 2,851,253

SOCKET AND SNAP-IN CONTACT FOR PRINTED CIRCUITS Filed Dec. 31, 1956 33a4 .34 3/ Z2 30 2.9 32 30 Z7 2.9 44 4 3 32 26 J), /3 /Z /4 2p \l 40 7 Iv 33 25 INVENTOR ATTORNEY United States Patent @fiice 2,861,253 PatentedNov. 18, 1958 SOCKET AND SNAP-IN CONTACT FOR PRINTED CmCUITS Bengt J.Johanson, Des Plaines, Ill., assignor to Cinch ManufacturingCorporation, Chicago, 111., a corporation of Illinois ApplicationDecember 31, 1956, Serial No. 631,749

4 Claims. (Cl. 339-417) This invention relates to a socket structure forvacuum tubes and other space discharge devices, and more especially tosuch a socket and snap-in contact arrangement particularly suited foruse in printed circuits.

Traditionally, tube sockets have had their terminals or contacts securedin the openings therein provided for that purpose by swaging theterminals adjacent the ends of the openings, or by other terminalexpanding means that also necessitate the use of suitable tools andseparate operations. In recent years, there has been a departure fromthis technique as a result of the development of snap-in terminals thatform an automatic interlock with the socket casting when inserted intothe openings thereof. The present invention is concerned with snap-interminals, but has for an object thereof the provision of an improvedsnap-in terminal and socket arrangement.

Another object of the invention is to provide an assembly of thischaracter wherein the terminal is easily inserted into the openingtherefor in the socket casting, but when in place 'is firmly anchoredtherein. Still another object is in the provision of a socket assemblyhaving snap-in terminals, and wherein the terminals when in place arelocked against movement in one direction by locking fingers that seatwithin recesses therefor in the casting, and which look against movementin the opposite direction by engagement of the terminal tail with anouter surface of the casting whereby when the terminal tails are pressedthrough openings therefor in a printed wire panel, the resultant forceexerted on the tail is transferred directly to the relatively large,rigid casting surface, with the result that there are no stresses placedon the locking fingers and on the thin edges of the recesses thatreceive the same.

p A further object is that of providing a snap-in terminal and socketcasting combination, in which the terminal has a prong-receiving socket,and locking fingers and terminal tail offset therefrom-the lockingfingers being spaced apart and received within recesses therefor in thecasting, and separated in the casting by an elongated rib defining aside of the prong-receiving socket so that when a tube pin is insertedthereinto, the rib in being positioned therebe tween determines theminimum spacing between the fingers and insures seating thereof in therecesses. Still a further object is to provide in such structure, pointsof engagement between the socket and terminal spaced from each otheralong a radial line to prevent movement of the terminal in one directionand also to prevent twisting of the terminal-the locking fingersfunctioning to prevent movement of the terminal in an oppositedirection. Additional objects and advantages will become apparent as thespecification develops.

An embodiment of the invention is illustrated in the accompanyingdrawing, in which Figure 1 is a perspective view of a socket embodyingthe invention; Figure 2 is an enlarged perspective view of one of theterminals of the socket; Figure 3 is an enlarged end view in elevationof the terminal taken along the line 33 of Figure 2; Figure 4 is anenlarged bottom plan view of the terminal taken along the line 44 ofFigure 3; Figure 5 is a transverse sectional view of the socket, viewedalong the line 55 of Figure 1; Figure 6 is a vertical sectional view ofthe socket as seen along the line 6-6 of Figure 5; and Figure 7 is afragmentary bottom plan view.

The socket assembly illustrated in the drawing comprises a socketcasting 10 equipped with a plurality of terminals 11 which arefrequently referred to as pins or contacts. As the socket is illustratedin Figures 1, 5 and 6, it is upside down or reversed-the surface 12 ofthe casting ordinarily being on the bottom adjacent the surface of theprinted wire panel or board with which the socket herein shown isadapted to. be used. It is illustrated in this position for conveniencein that the terminals 11 are inserted into position within the casting10 from the bottom side 12 thereof.

The casting 11 may be provided with a central opening 13 extendingtherethrough that customarily will have a grounding terminal (not shown)mounted therein for connection to the ground wire of a printed circuit.Con, centric about the central opening 13 are a plurality of arcuatelyspaced terminal-receiving openings 14. Along the upper side 15 of thecasting is an annular channel 16 that has opening thereinto at spacedpoints therealong the pin-receiving apertures 17 for receiving the pinsof a tube. The channel'16 facilitates alignment of the tube pins withthe respective apertures 17 for insertion of the pins thereinto. Asshown in Figure 1, the bottom surface of the casting may have thereon aplurality of spaced apart, radially extending ribs 18 interposed betweeneach of the openings 14, and these serve as barriers to separate theadjacent contacts 11. a

The opening 14 is generally rectangular throughout except for the innerportion of each adjacent the wall 15 which is filled with asquare-shaped abutment that defines the pin-receiving aperture 17. Theouter wall of these abutment members are seen in Figures 5 and 6, andare designated with the numeral 19. Along the surface 12 of the casting10, each opening 14 is slightly enlarged to define a perimetric entrancearea 20 with diverging side wal1s, as is most apparent from Figure 6.

The outer portion of each opening 14 is compartmented by a verticallyextending rib 21, the compartments for identification being designatedin Figure 6 with the numerals 22 and 23, respectively. The inner edge ofthe rib 21, as is most clear from Figure 5, terminates on a line withthe outer edge of the abutment wall 19. The

spaced members and numbered, respectively; 29 and 30.

The tail 26, as shown in Figures land 5, extends outwardly of thecasting 10 when the terminals are in place therein, and are adapted toextend through openings provided therefor in a printed Wire board (notshown) for connection with the printed wires thereon. The pinreceivingmembers 27 and 28 are offset from the tall 26, and theirlongitudinal'axes are generally parallel thereto. The locking fingers 29and 30 flare outwardly and extend from the members 2'7 and 28 in thedirection of the offset of the tail 26. Preferably, each of the pincontactor members 27 and 28 have an inwardly bowed central section 31and 32, respectively, for frictionally gripping the pin of a tubeinserted thereintoso as to firmly hold Such pin and establish a goodelectrical connection therewith.

As seen in Figure 4, the tail 26 may be curved in section for purposesof stiffening it; and as shown in Figure 2, the spaced apartpin-receiving members and the tail are formed integrally with eachother, and are so interconnected by intermediate portions 33 and 34.Such intermediate sections have the outer edges thereof turned inwardlytoward each other (as shown at 35 and 36 in Figure 6), While theopposite edges thereof have depending cars 37 that aid in supporting thecontact to prevent any rocking thereof which might disengage "thelocking fingers.

In assembling the terminals 11 with the casting 10, the terminals areheld in position as shown in Figures 1 and with the spring fingers 29and 30 adjacent the surface 12 of the casting. The terminals are alignedwith the respective openings 14 in the casting; and as the springfingers are'moved theretoward, the inclined edges of the perimetricframe (that defines the outer edge of the opening) cam the springfingers inwardly so that the terminal can then'ber'noved downwardly inthe direction of the arrow shown in Figure 5 to insert it into theopening.

During fliis downward movement, the spring fingers 29 and 30 rub alongthe outer walls of the compartments 22 and 23 of the opening 14, andultimately align with the recesses 24 and 25 in such walls. Then, thespring fingers seat in the recesses, and through engagement of therespective shoulders 38 and 39 constrain the terminal against movementin the opposite direction. Thus, the terminals cannot now be withdrawnfrom the openings.

'At the same time, wall portions of the intermediate sections 33 and 34of the terminal substantially abut the shoulder or wall portion 49 atthe outer side of each of the openings 14 adjacent the frame 20 thereof.Such abutment prevents further downward movement of the terminal withrespect to the casting. Concurrently therewith, the contact-receivingmembers 27 and 28 along the lower edges thereof engage the upper surfaceof the abutment member 19, and further constrain downward movement ofthe terminal. Thus, the terminals are locked Within the openings 14 byengagement of the locking fingers '29 and 30 with the shoulders 38 and39 of the recessed wall portions, and by engagement of the intermediatesections 33 and 34 with the shoulders 40, and by further engagement ofthe pin-receiving members 27 and 28 with the abutments 19.

It will be apparent that the terminals are inserted by a direct movementthereof longitudinally with respect to the openings 14, so that thenecessity of turning or twisting or cocking the terminals during suchinsertion is obviated; yet a firm, positive interlock automaticallyeifectuated by the complete insertion of the terminals thereby anchorsthem in place and prevents movement of the terminals along longitudinallines. The seating of the terminals at two radially spaced pointsnamely,the abutment member 19 and shoulder 4ll--prevents twisting of theterminal during insertion and withdrawal of atube pin so that noabnormal stresses are placed on the terminal, and particularly on thelocking fingers 29 and 30 thereof. Thus, there is little likelihood thatthe terminals will ever be damaged by mounting and removal of tubes fromthe socket, and therefore they can be made of relatively thin stockthat, of course, decreases the cost thereof.

Further, the vertically extending ribs 21 are received between thelocking fingers 29 and 30 when the terminals are inserted into theopenings 14,'and if for any reason suchfingers should be compressedtoward each other, the rib will cam them outwardly whereby it is assuredthat these fingers will seat within the locking recesses 24 and 25.Thus, the necessity of maintaining a precise or accurate dimensionalspacing between the fingers 29 and 30 is ieliminatedthe Ill) 21 insuringthat these members will be spread apart widely enough to seat within therecesses '24 and 25, and the converging walls of the frame 20 carnmingthe spring fingers toward each other if necessary to insure insertionthereof into the opening.

While in the foregoing specification, the invention has been describedand illustrated in detail as to an embodiment thereof, it will beapparent to those skilled in the art that numerous variations may bemade of those details without departing from the spirit and principlesof the invention.

I claim:

1. A snap-in terminal and casting assembly providing a socket for aspace discharge device, said casting having a plurality of arcuatelyspaced openings therethrough, each of said openings being generallyrectangular and raving along the outer side-thereof a rib extendinglongitudinally therein to define substantially parallel compartments,each opening having also therein at one end an abutment member providedwith an aperture therethrough adapted to receive a contact of such aspace discharge device, and a terminal mounted in each of said openingsand having a tail extending outwardly from said casting for connectionwith the wires ofa printed circuit, each of said terminals having spacedapart pin-receiving portions adapted to receive the pin of a spacedischarge device therebetween for making electrical contact therewith, apair of locking fingers, one carried by each of said pin-receivingportions, said locking fingers being aligned with each other and flaringoutwardly at the ends thereof, each of said compartments having in awall thereof a recess receiving a locking finger therein, the spacedpin-receiving portions being in substantial engagement with saidabutment members, said casting providing .a shoulder for each of saidopenings along the outer edge thereof in substantial abutment with theterminal therein, said abutment member and said shoulder being orientedin the same direction and being spaced apart along a radial line throughthe opening thereof for constraining movement of the terminal thereof inone direction and to prevent rotation thereof, said locking fingers andrecesses being cooperatively related to prevent movement of therespective terminals in the opposite direction.

2. The structure of claim 1 in which said casting is provided with arecessed frame defining the end of each of said openings through whichthe terminals are passed, said recessed frame having inwardly convergingside walls for camming said locking fingers toward each other during theinsertion of the terminals into the respective openings. 7

3. In a socket assembly of the character described, a casting providedwith an opening therein extending transversely therethrough, oppositewalls of the casting defining said opening each having a recess therein,a terminal positioned Within said opening and having locking fingersseated within said recesses to prevent movement of said terminal in onedirection out of the opening, said casting having a rib positioned insaid opening and-extending longitudinally thereof, said rib beinginterposed between said locking fingers, and said casting and terminalhaving cooperating means for preventing movement of said terminal out ofsaid opening in the opposite direction.

4. In combination, a socket casting having a plurality of spaced apartopenings therein and apertures aligned therewith for receiving the pinsof a tube, each of said openings having locking recesses in spaced apartwalls thereof, a terminal mounted in each of said openings, each of saidterminals having a pin-receiving portion aligned with an aperture formaking contact with a pin received therein, spaced apart locking fingerscarried by said pin-receiving portion and being seated inthe respectiverecesses to prevent movement ofthe terminal outwardly of said opening,in one direction, said casting having a rib positioned in each of saidopenings and extending longitudinally thereof, each of said ribs beinginterposed between said spaced apart locking fingers of said respectiveterminal for maintaining a minimum spacing therebetween when theterminals are inserted into said respective openings, an abutment memberpro vided by said casting in each of said openings and being insubstantial engagement with said terminal to prevent movement thereof inan opposite direction out of said opening, and a wall portion providedby said casting for each of said openings and also being in substantialengagement with said terminal to prevent movement there- 5 and removalof the pins of a tube.

References Cited in the file of this patent UNITED STATES PATENTS 102,205,146 Larkin June 18, 1940 2,694,799 Del Camp Nov. 16, 19542,793,353 Del Camp May 21, 1957

